1. Field of the Invention
This invention relates to an accumulator with a refrigerant processing cartridge for an automotive air conditioning system.
2. Disclosure Information
Automotive air conditioning systems typically use Freon as a refrigerant. An air conditioning compressor in the system compresses Freon for delivery to an air conditioning condenser where the state of the refrigerant changes from gas to liquid. The outlet side of the condenser is connected to an expansion device and to an evaporator where the refrigerant changes state from a liquid to a gas. An air blower circulates air over the evaporator to the vehicle passenger compartment causing heat transfer to occur from the ambient air to the evaporator.
The outlet side of the evaporator in some air conditioning systems is connected to an accumulator that contains a liquid-gas separator. The separator causes liquid components of the refrigerant to be separated from the gaseous component before the gaseous component is returned to the compressor. The accumulator also provides for recovery of lubricating oil contained in the refrigerant gas and for returning a metered amount of lubricating oil to the inlet side of the compressor for lubrication purposes. Because the accumulator is connected to the inlet side of the compressor, the reduced absolute pressure in the accumulator causes a portion of the liquified refrigerant to return to the gaseous state, whereupon it is returned to the inlet side of the compressor. An example of a prior art air conditioning accumulator is shown in FIG. 1 of the specification and described in U.S. Pat. No. 4,474,035, which is assigned to the assignee of the present invention.
An example of an accumulator for use on the high pressure side of a refrigeration system is shown in U.S. Pat. No. 3,778,984 which is also assigned to the assignee of the present invention. Both arrangements, regardless of whether the accumulator or separator is on the inlet side of the compressor or on the high pressure or outlet side of the compressor, function to separate liquid refrigerant from gaseous refrigerant and for separating the lubricating oil from the gas.
The amount of liquid retained in the accumulator of the present invention depends upon the conditions under which the system operates. Regardless, however, of the amount of liquid retained in the accumulator, the accumulator functions to allow only vapor to be returned to the compressor together with a very small metered amount of lubricating oil.
Designers have employed a variety of schemes for arranging accumulators or oil separators for use with compressors. In the usual case, the working fluid of the system is circulated to the accumulator tank, where the vapor components are caused to rise in the tank and are drawn off through a filter. Typically, all of the vapor passing from the accumulator or separator must first pass through the filter element. The following U.S. patents generally describe such types of accumulators or separators: U.S. Pat. Nos. 1,672,571; 3,633,377; 4,173,440; 4,289,461; and 4,553,906. Further, British Pat. No. 1,512,507 and German Pat. Nos. 2,720,214 and 3,506,433 describe similar systems for separating and filtering oil from the working fluid of a compressor. Each of these devices employs a single flow path for the working fluid being returned to the compressor. This is disadvantageous inasmuch as a blockage of the single flow path will cause failure of the refrigerating system.
U.S. Pat. No. 2,608,269 describes an oil separator for a refrigeration system in which all of the gases and oil entering the oil separator must first pass through a solid adsorbent block and then through a matted mesh strainer before passing out of the separator. This type of system as well as systems described in U.S. Pat. Nos. 4,331,001 and 4,509,340 suffer from a common deficiency inasmuch as the refrigerant may be subjected to an excessively high pressure drop occasioned by the requirement of passage along a single flow path through not only a screen element but also through a desiccant or dehydrator material. The latter two patents describe automotive air conditioning accumulator assemblies in which a cartridge including a desiccant material has an outlet extending from the cartridge at a right angle to the axis of the accumulator. These cartridges are not well suited, therefore, to automated assemblies of the accumulators because the cartridges are not susceptible to axial insertion into the upper portion of the cylindrical housing of the accumulator.
It is an object of the present invention to provide an accumulator with a refrigerant processing cartridge which is axially inserted within the housing of the accumulator.
It is yet a further object of the invention to provide an accumulator with an axially insertable refrigerant cartridge including drier means for removing moisture from refrigerant, filter means for removing particulate matter from refrigerant, and separator means for promoting the separation of liquid and vapor components of the refrigerant.
It is yet a further object of the present invention to provide an accumulator with an axially insertable refrigerant processing cartridge which may be inserted by an automated assembly process.
It is yet another object of the present invention to provide an accumulator having an axially insertable refrigerant processing cartridge which may be replaced when the cartridge becomes excessively soiled or otherwise spent.
It is yet another object of the invention to provide a refrigerant processing cartridge for use in the accumulator of an air conditioning system wherein the cartridge has a dual flow path for the refrigerant in order that the refrigerant will not be subjected to an unduly great flow restriction on its way through the accumulator.
Other objects, features and advantages of the present invention will become apparent through the following description of the invention.